Question 1026253:  $20,862 is invested, part at 9% and the rest at 7%. If the interest earned from the amount invested at 9% exceeds the interest earned from the amount invested at 7% by $831.50, how much is invested at each rate? 
 Answer by addingup(3677)      (Show Source): 
You can  put this solution on YOUR website! There is an amount invested at 9%. We don't know how much it is, so we will call it x. 
There is another amount invested at 7%, and we know that this is equal to 20,862-x. 
And the problem says: 
0.09x = 0.07(20,862-x)+831.50 Multiply on right to get rid of parenthesis 
0.09x = 1,460.34-0.07x+831.50 
0.09x = 2,291.84-0.07x add 0.07x on both sides: 
0.16x = 2,291.84 divide both sides by 0.16 
x = 14,324 this is the amount invested at 9% 
And: 
20,862-14,324 = 6,538 is invested at 7% 
Happy learning, 
J 
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